Anesthetic management in pregnant women with Fontan circulation: a case series.

BACKGROUND: Given the advances in medicine, women with Fontan circulation are now reaching childbearing age. However, data on the mode of delivery and anesthetic management of these patients are limited. We report the cases of five pregnant women with Fontan circulation. CASE PRESENTATION: The mean age at delivery was 28 ± 3 years, and the mean gestational period was 34 weeks and 3 days. Anticoagulation therapy was switched from warfarin and aspirin to continuous intravenous heparin. The modes of delivery were scheduled cesarean section (C/S) in one, emergency C/S in three, and vaginal delivery with epidural labor analgesia in one patient. Three patients underwent C/S under regional anesthesia; one received general anesthesia. The perinatal complications were heart failure, worsening valve regurgitation, and postoperative hematoma in three, four, and two patients, respectively. CONCLUSIONS: For C/S in women with Fontan circulation, regional anesthesia should be considered. Epidural labor analgesia can help prevent the decrease in pulmonary blood flow due to straining. We initiated labor analgesia or C/S with regional anesthesia at the appropriate time in four patients.

Gene Deletion Algorithms for Minimum Reaction Network Design by Mixed-Integer Linear Programming for Metabolite Production in Constraint-Based Models: gDel_minRN.

Genome-scale constraint-based metabolic networks play an important role in the simulation of growth-coupled production, which means that cell growth and target metabolite production are simultaneously achieved. For growth-coupled production, a minimal reaction-network-based design is known to be effective. However, the obtained reaction networks often fail to be realized by gene deletions due to conflicts with gene-protein-reaction (GPR) relations. Here, we developed gDel_minRN that determines gene deletion strategies using mixed-integer linear programming to achieve growth-coupled production by repressing the maximum number of reactions via GPR relations. The results of computational experiments showed that gDel_minRN could determine the core parts, which include only 30% to 55% of whole genes, for stoichiometrically feasible growth-coupled production for many target metabolites, which include useful vitamins such as biotin (vitamin B7), riboflavin (vitamin B2), and pantothenate (vitamin B5). Since gDel_minRN calculates a constraint-based model of the minimum number of gene-associated reactions without conflict with GPR relations, it helps biological analysis of the core parts essential for growth-coupled production for each target metabolite. The source codes, implemented in MATLAB using CPLEX and COBRA Toolbox, are available on https://github.com/MetNetComp/gDel-minRN.

SPONTANEOUS CLOSURE OF MACULAR HOLE AFTER VITRECTOMY FOR MYOPIC RETINOSCHISIS WITH FOVEAL DETACHMENT.

PURPOSE: To discuss a case of a macular hole formation after vitrectomy for myopic retinoschisis with foveal detachment and spontaneous closure, during long-term follow-up. METHODS: Case report. RESULTS: A 71-year-old man with myopic retinoschisis with foveal detachment had a vitrectomy with internal limiting membrane peeling combined with cataract surgery in the left eye. The preoperative best-corrected visual acuity was 8/20, and the axial length was 27.11 mm. A macular hole with foveal detachment was observed 1 month after surgery. However, the macular hole closed spontaneously with foveal detachment at 4 months of follow-up. Foveal detachment resolved, and the best-corrected visual acuity improved to 20/20 at nine months of follow-up. CONCLUSION: This case suggests that the macular hole formed after vitrectomy for myopic retinoschisis with foveal detachment with internal limiting membrane peeling can close spontaneously.

Prevalence of and factors associated with dilated choroidal vessels beneath the retinal pigment epithelium among the Japanese.

Pachyvessels are pathologically dilated large choroidal vessels and are associated with the pathogenesis of several pachychoroid-related disorders, including central serous chorioretinopathy. We aimed to investigate the prevalence of and risk factors for pachyvessels in the Japanese population. We included 316 participants (aged ≥ 40 years) with normal right eyes. The presence of pachyvessels (vertical diameter > 300 µm, distance to the retinal pigment epithelium < 50 µm) was determined using 6 × 6 mm macular swept-source optical coherence tomography images, and associated risk factors were investigated. Subfoveal choroidal thickness was measured, and its associated risk factors investigated. The overall prevalence of pachychoroids was 9.5%. Regression analysis showed that a younger age, shorter axial length, male sex, and smoking were significantly associated with the presence of pachyvessels (p = 0.047; odds ratio [OR] 0.96 per year, p = 0.021; OR 0.61 per 1 mm, p = 0.012; OR 3.08 vs. female, and p = 0.011; OR 3.15 vs. non-smoker, respectively) and greater choroidal thickness (p < 0.001, p < 0.001, p < 0.003, and p < 0.017, respectively). The results were consistent with other research findings which showed that pachychoroid-related disorders such as central serous chorioretinopathy were associated with younger age, male sex, shorter axial length, and smoking. Smoking may be associated with choroidal circulatory disturbance in the Japanese population.

Evaluation of PCR conditions for characterizing bacterial communities with full-length 16S rRNA genes using a portable nanopore sequencer.

MinION (Oxford Nanopore Technologies), a portable nanopore sequencer, was introduced in 2014 as a new DNA sequencing technology. MinION is now widely used because of its low initial start-up costs relative to existing DNA sequencers, good portability, easy-handling, real-time analysis and long-read output. However, differences in the experimental conditions used for 16S rRNA-based PCR can bias bacterial community assessments in samples. Therefore, basic knowledge about reliable experimental conditions is needed to ensure the appropriate use of this technology. Our study concerns the reliability of techniques for obtaining accurate and quantitative full-length 16S rRNA amplicon sequencing data for bacterial community structure assessment using MinION. We compared five PCR conditions using three independent mock microbial community standard DNAs and established appropriate, standardized, better PCR conditions among the trials. We then sequenced two mock communities and six environmental samples using Illumina MiSeq for comparison. Modifying the PCR conditions improved the sequencing quality; the optimized conditions were 35 cycles of 95 °C for 1 min, 60 °C for 1 min and 68 °C for 3 min. Our results provide important information for researchers to determine bacterial community using MinION accurately.

Anesthetic management of laparoscopy-assisted total proctocolectomy in a cardiac sarcoidosis patient with a cardiac resynchronization therapy-defibrillator: a case report.

BACKGROUND: Cardiac sarcoidosis (CS) causes severe conduction abnormalities and arrhythmias. CS patients are increasingly being treated with cardiac resynchronization therapy-defibrillators (CRT-Ds). For the first time, we report the anesthetic management of a CS patient with a CRT-D. CASE PRESENTATION: A 65-year-old male with an implanted CRT-D due to CS was scheduled for a laparoscopy-assisted total proctocolectomy for his transverse colon cancer. His left ventricular ejection fraction was 32.0%, and his physical status was a New York Heart Association class III. General and epidural anesthesia were performed while using standard monitors and a FloTracTM system. The dual-chamber pacing (DDD) modality of the CRT-D was unchanged, and its defibrillation function was deactivated before surgery. The surgery was successfully performed, and the patient was discharged without worsening of his cardiac condition. CONCLUSIONS: A detailed understanding of this patient's condition, as well as sarcoidosis, helped to facilitate successful anesthetic management of this patient.

Association Between Retinal Layer Thickness and Perfusion Status in Extramacular Areas in Diabetic Retinopathy.

PURPOSE: This study was performed to investigate the association between changes in retinal layer thickness and perfusion status in the extramacular areas of eyes with diabetic retinopathy. DESIGN: Retrospective cross-sectional study. METHODS: The medical records of 70 eyes from 55 patients with diabetes were reviewed. The status of retinal perfusion in extramacular areas was evaluated using swept-source optical coherence tomography angiography. Retinal layer thickness was measured in nonperfused areas (NPA) larger than 2 optic disc areas, areas of sparse capillaries (SC), and perfused areas (PA-DR) in eyes with diabetic retinopathy. Retinal layer thickness was also measured in perfused areas in eyes without diabetic retinopathy (PA-NDR), and the thicknesses were then compared. In addition, swept-source optical coherence tomography angiography images and retinal thickness maps were compared to investigate the distribution of retinal thickness changes and spatial relationships to areas of retinal perfusion. RESULTS: The inner retinal thickness in NPA was significantly thinner than the inner retinal thicknesses in SC, PA-DR, and PA-NDR (all P < .001), and the inner retinal thickness in PA-NDR and SC was significantly thinner than that in PA-DR (P = .006 and .031, respectively). In a distribution analysis of the extramacular areas, NPA spatially overlapped with areas of severe retinal thinning in all locations. Local thickening with smooth shapes and gentle borders overlapped with areas of capillary abnormalities. Neovascularization was present at sites of local thickening with irregular shapes and unnatural clear borders. CONCLUSIONS: Changes in retinal layer thickness were associated with perfusion status, suggesting that retinal thickness maps can reflect perfusion status.

DIAGNOSTIC CHARACTERISTICS OF POLYPOIDAL CHOROIDAL VASCULOPATHY BASED ON B-SCAN SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY AND ITS INTERRATER AGREEMENT COMPARED WITH INDOCYANINE GREEN ANGIOGRAPHY.

PURPOSE: To examine the characteristics of polypoidal choroidal vasculopathy using B-scan optical coherence tomography angiography (OCTA), and determine the diagnostic criteria of polypoidal choroidal vasculopathy based on OCTA. METHODS: This retrospective case series included patients diagnosed with treatment-naïve polypoidal choroidal vasculopathy who underwent indocyanine green angiography (ICGA) and swept-source OCTA at baseline. We compared the characteristics of the polyps detected using B-scan OCTA and ICGA. Then, the diagnostic concordance of each polypoidal lesion between ICGA and OCTA was evaluated. RESULTS: Among 54 eyes of 52 patients, all 54 eyes showed flow signals indicating polyps on both ICGA and B-scan OCTA. All polyps on B-scan OCTA were detected as round/ring-like flow signals inside pigment epithelial detachments, incomplete round/ring-like flow signals overlaid with round/ring-like OCT structures inside pigment epithelial detachments, or flow signals adjacent to a pigment epithelial detachment notch. Using B-scan OCTA, 94.7% of the polypoidal lesions were detected by an independent evaluator with an overall accuracy of 92.6% for counting the polypoidal lesions per eye relative to ICGA and a Kappa value of 0.82. CONCLUSION: Polyp detection on B-scan OCTA demonstrates high accuracy and is comparable to that obtained on ICGA. B-scan OCTA could replace ICGA for the diagnosis of polypoidal choroidal vasculopathy.

CHARACTERISTICS AND CLASSIFICATION OF TYPE 3 NEOVASCULARIZATION WITH B-SCAN FLOW OVERLAY AND EN FACE FLOW IMAGES OF OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

PURPOSE: To study B-scan flow overlay and en face flow optical coherence tomography angiography (OCT-A) images of Type 3 neovascularization (NV) and to characterize a staging system for Type 3 NV based on the OCT-A findings. METHODS: We retrospectively collected data on consecutive treatment-naive eyes with Type 3 NV. All eyes underwent fluorescein angiography, indocyanine green angiography, structural spectral domain OCT, and OCT-A (AngioPlex). Localization and extension of abnormal flows detected by B-scan flow overlay and en face OCT-A images were assessed. RESULTS: Of 24 eyes of 22 patients with Type 3 NV, B-scan flow overlay images showed that 4.2% had telangiectatic flow in the deep retinal layer without outer plexiform layer disruption (Stage 1), 8.3% had downward intraretinal flow and subretinal flow without retinal pigment epithelium disruption (Stage 2), and 87.5% had downward flow and retinal pigment epithelium disruption (Stage 3). Of the Stage 3 eyes, 95.2% showed flow signal penetrating at the site of the retinal pigment epithelium disruption on the B-scan flow overlay images. CONCLUSION: We showed the characteristics of Type 3 NV using B-scan flow overlay and en face OCT-A images. B-scan flow overlay OCT-A images seem useful to improve the detection and accurate diagnosis of Type 3 NV.

Vascular maturity of type 1 and type 2 choroidal neovascularization evaluated by optical coherence tomography angiography.

PURPOSE: Vessel maturation is considered to proceed by pruning branches resulting in less branching vessels. This study investigated the vessel junction densities of type 1 and type 2 choroidal neovascularizations (CNVs) using optical coherence tomography angiography (OCTA). METHODS: We collected consecutive data from treatment-naïve eyes diagnosed with typical age-related macular degeneration (AMD). The OCTA images with CNV were analyzed to calculate vessel areas, vessel lengths, and vessel junction densities. RESULTS: Of 60 eyes in 60 patients, type 1 CNV diagnoses had been made in 40 eyes, and type 2 CNV in 20 eyes. We found no significant difference in vessel areas between type 1 CNV and type 2 CNV (type 1 CNV, 0.44 ± 0.37 mm2; type 2 CNV, 0.37 ± 0.48 mm2), and no significant difference in vessel lengths (type 1 CNV, 18.24 ± 15.96 mm; type 2 CNV, 16.13 ± 21.45 mm). However, the vessel junction density of type 1 CNV was significantly lower than that of type 2 CNV by 16.0% (P = 0.008). CONCLUSION: OCTA revealed that the vessel junction densities of type 1 CNVs were lower than those of type 2 CNVs, suggesting type 1 CNV vessels are more mature than type 2 CNV vessels.

A Robust Method for the Determination of Cr(VI) and Cr(III) in Industrial Wastewaters by Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry Combined with a Chelating Pretreatment with 2,6-Pyridinedicarboxylic Acid.

We have developed a method for the determination of Cr(VI) and Cr(III) in industrial wastewater by liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS) combined with a chelating pretreatment with 2,6-pyridinedicarboxylic acid (PDCA). The PDCA unified the chemical forms of the Cr(III) species in water samples by the formation of a stable Cr(III)-PDCA complex, which was then separated by a LC column. The chromatographic mobile phase at neutral pH and the column of a mixed-bed of anion and cation exchangers successfully separated not only the chromium species without any redox conversion, but also chloride, which interfered with ICP-MS detection. The method detection limits measured at m/z 53 were 0.66 µg of Cr L-1 for Cr(III) and 0.74 µg L-1 for Cr(VI) with a sample injection volume of 20 µL under a no gas mode. The recoveries of spiked Cr(VI) at 50 and 500 g L-1 into the fifteen kinds of industrial wastewater samples were satisfactory (>90%). The proposed method for the determination of Cr(VI) was also validated by comparing with a colorimetric method using 1,5-diphenylcarbazide prescribed by the ISO 11083 and the JIS K0102.

Effect of sex and polymorphisms of CYP2B6 and UGT1A9 on the difference between the target-controlled infusion predicted and measured plasma propofol concentration.

INTRODUCTION: To examine whether sex and polymorphisms of cytochrome P450 (CYP) 2B6 and UDP-glucuronosyltransferase (UGT) 1A9 affect the difference between predicted and measured plasma propofol concentration during continuous infusion by target-controlled infusion. RESULTS: Blood samples of 69 patients (48 men and 21 women) were obtained at 4 h after initial propofol infusion. Percentage performance error (PE) was calculated to assess the difference between measured and predicted propofol concentration. Regression coefficients (ß) and 95% confidence intervals (CI) of sex and the polymorphisms of CYP2B6 and UGT1A9 for PE were, separately and mutually, estimated with linear regression. Covariates included age and body mass index in the minimal adjusted model, and additionally included clinical factors (mean blood pressure, heart rate, volume of intravenous fluid, surgical site, surgical position, and pneumoperitoneum) in the full adjusted model. PE was higher in men than in women (28.7% versus 10.5%, p = 0.015). Female sex was inversely associated with PE: the minimal adjusted ß = - 8.84 (95% CI, - 16.26 to - 1.43); however, the fully adjusted ß with clinical factors became not significant. The average of PE did not differ between polymorphisms of CYP2B6 and UGT1A9, and ß of CYP2B6 516G>T polymorphisms mutually adjusted with female sex was not significant. Mean blood pressure, heart rate, and volume of intravenous fluid were independently associated with PE in the full adjusted model. CONCLUSIONS: Under 4 h anesthesia with propofol target-controlled infusion in our population, sex differences appeared to exist in the propofol concentration, which might be largely mediated by clinical factors, such as hemodynamic status. TRIAL REGISTRATION: UMIN-CTR UMIN000009015 , Registered 1 October 2012.

Data integration aids understanding of butterfly-host plant networks.

Although host-plant selection is a central topic in ecology, its general underpinnings are poorly understood. Here, we performed a case study focusing on the publicly available data on Japanese butterflies. A combined statistical analysis of plant-herbivore relationships and taxonomy revealed that some butterfly subfamilies in different families feed on the same plant families, and the occurrence of this phenomenon more than just by chance, thus indicating the independent acquisition of adaptive phenotypes to the same hosts. We consequently integrated plant-herbivore and plant-compound relationship data and conducted a statistical analysis to identify compounds unique to host plants of specific butterfly families. Some of the identified plant compounds are known to attract certain butterfly groups while repelling others. The additional incorporation of insect-compound relationship data revealed potential metabolic processes that are related to host plant selection. Our results demonstrate that data integration enables the computational detection of compounds putatively involved in particular interspecies interactions and that further data enrichment and integration of genomic and transcriptomic data facilitates the unveiling of the molecular mechanisms involved in host plant selection.

2,5-Dimethylcelecoxib prevents pressure-induced left ventricular remodeling through GSK-3 activation.

Glycogen synthase kinase-3 (GSK-3) is a crucial regulator of cardiac hypertrophy. We previously reported that 2,5-dimethylcelecoxib (DM-celecoxib), a celecoxib derivative unable to inhibit cyclooxygenase-2, prevented cardiac remodeling by activating GSK-3, resulting in lifespan prolongation in a mouse model of genetic dilated cardiomyopathy. In the present study, we investigated whether DM-celecoxib can also prevent pressure-induced cardiac remodeling and heart failure, elicited by transverse aortic constriction (TAC). Before testing the effects of DM-celecoxib, we compared the effects of TAC on the hearts of wild-type and GSK-3ß hetero-deficient (GSK-3ß+/-) mice to determine the role of GSK-3 in cardiac remodeling and heart failure. GSK-3ß+/- mouse hearts exhibited more severe hypertrophy, which was characterized by accelerated interstitial fibrosis, than wild-type mouse hearts after TAC, suggesting that reduced GSK-3ß activity aggravates pressure-induced left ventricular remodeling. We subsequently examined the effects of DM-celecoxib on TAC-induced cardiac remodeling. DM-celecoxib inhibited left ventricular systolic functional deterioration, and prevented left ventricular hypertrophy and fibrosis. It also activated GSK-3α and ß by inhibiting Akt, suppressing the activity of ß-catenin and nuclear factor of activated T-cells and thereby decreasing the expression of the Wnt/ß-catenin target gene products fibronectin and matrix metalloproteinase-2. These results suggest that DM-celecoxib is clinically useful for treating pressure-induced heart diseases.

Characterization of Piperacillin/Tazobactam-Resistant Klebsiella oxytoca Recovered from a Nosocomial Outbreak.

We characterized 12 clinical isolates of Klebsiella oxytoca with the extended-spectrum ß-lactamase (ESBL) phenotype (high minimum inhibitory concentration [MIC] values of ceftriaxone) recovered over 9 months at a university hospital in Japan. To determine the clonality of the isolates, we used pulsed-field gel electrophoresis (PFGE), multi-locus sequence typing (MLST), and PCR analyses to detect blaRBI, which encodes the ß-lactamase RbiA, OXY-2-4 with overproduce-type promoter. Moreover, we performed the isoelectric focusing (IEF) of ß-lactamases, and the determination of the MICs of ß-lactams including piperacillin/tazobactam for 12 clinical isolates and E. coli HB101 with pKOB23, which contains blaRBI, by the agar dilution method. Finally, we performed the initial screening and phenotypic confirmatory tests for ESBLs. Each of the 12 clinical isolates had an identical PFGE pulsotype and MLST sequence type (ST9). All 12 clinical isolates harbored identical blaRBI. The IEF revealed that the clinical isolate produced only one ß-lactamase. E. coli HB101 (pKOB23) and all 12 isolates demonstrated equally resistance to piperacillin/tazobactam (MICs, >128 µg/ml). The phenotypic confirmatory test after the initial screening test for ESBLs can discriminate ß-lactamase RbiA-producing K. oxytoca from ß-lactamase CTX-M-producing K. oxytoca. Twelve clinical isolates of K. oxytoca, which were recovered from an outbreak at one university hospital, had identical genotypes and produced ß-lactamase RbiA that conferred resistance to piperacillin/tazobactam. In order to detect K. oxytoca isolates that produce RbiA to promote research concerning ß-lactamase RbiA-producing K. oxytoca, the phenotypic confirmatory test after the initial screening test for ESBLs would be useful.

Rapid reversal of neuromuscular blockade by sugammadex after continuous infusion of rocuronium in patients with liver dysfunction undergoing hepatic surgery.

OBJECTIVE: Sugammadex rapidly reverses neuromuscular blockade (NMB) induced by rocuronium. NMB induced by rocuronium is prolonged in patients with liver dysfunction, because the drug is mainly excreted into the bile. However, the efficacy and safety of sugammadex in terms of reversing rocuronium-induced NMB in patients with liver dysfunction undergoing hepatic surgery have not been evaluated. This observational study investigated the efficacy and safety of sugammadex after continuous infusion of rocuronium in patients with liver dysfunction undergoing hepatic surgery. METHODS: Remifentanil/propofol anesthesia was administered to 31 patients: 15 patients in the control group, and 16 patients from a group with liver dysfunction. Rocuronium (0.6 mg/kg) was administered, followed by continuous infusion. The enrolled patients were then subdivided into two groups according to the dose of sugammadex. In the first group a single dose of sugammadex (2.0 mg/kg) was given at the reappearance of the second twitch (T2). In the second group a single dose of sugammadex (4.0 mg/kg) was given at the first twitch response if T2 did not reappear in 15 minutes after stopping rocuronium. The primary outcome was time from administration of sugammadex to recovery of a train-of-four ratio to 0.9. RESULTS: The dose of rocuronium required in the liver dysfunction group was lower than that in the control group (6.2 vs. 8.2 µg/kg/min, p = 0.002). The mean time from the administration of sugammadex to recovery of the train-of-four ratio to 0.9 was not significantly different between the liver dysfunction group and the control group (2.2 minutes vs. 2.0 minutes in the 2 mg/kg administration group, p = 0.44 and 1.9 minutes vs. 1.7 minutes in the 4 mg/kg administration group, p = 0.70, respectively). No evidence of recurarization was observed in any of the patients. Most of the adverse events were found to be mild and such events were not related to the use of sugammadex. None of the patients was eliminated from the study because of an adverse event. One patient died due to cholestatic liver cirrhosis because of repeated hepatic surgery. CONCLUSION: Sugammadex can rapidly reverse NMB after continuous infusion of rocuronium in patients with liver dysfunction undergoing hepatic surgery. Sugammadex was found to be safe and well tolerated. However, further studies of sugammadex under similar conditions should be conducted involving a large number of patients with liver dysfunction undergoing hepatic surgery.

Cellulolytic environment in the midgut of the wood-feeding higher termite Nasutitermes takasagoensis.

Unlike lower termites, xylophagous higher termites thrive on wood without the aid of symbiotic protists. In the higher termite Nasutitermes takasagoensis, both endogenous endo-ß-1,4-glucanase and ß-glucosidase genes are expressed in the midgut, which is believed to be the main site of cellulose digestion. To further explore the detailed cellulolytic system in the midgut of N. takasagoensis, we performed immunohistochemistry and digital light microscopy to determine distributions of cellulolytic enzymes in the salivary glands and the midgut as well as the total cellulolytic activity in the midgut. Although cellulolytic enzymes were uniformly produced in the midgut epithelium, the concentration of endo-ß-1,4-glucanase activity and luminal volume in the midgut were comparable to those of the wood-feeding lower termite Coptotermes formosanus, which digests cellulose with the aid of hindgut protists. However, the size of ingested wood particles was considerably larger in N. takasagoensis than that in C. formosanus. Nevertheless, it is possible that the cellulolytic system in the midgut of N. takasagoensis hydrolyzes highly crystalline cellulose to a certain extent. The glucose produced did not accumulate in the midgut lumen. Therefore, the present study suggests that the midgut of the higher termite provides the necessary conditions for cellulolysis.

Inconspicuous matured males of worker form are produced in orphaned colonies of Reticulitermes speratus (Isoptera: Rhinotermitidae) and participate in reproduction.

Differentiation of neotenics is easily induced by orphaning the worker termites of Reticulitermes speratus (Kolbe). Although it has previously been reported that the sex ratio of neotenics is female-biased, the background of this phenomenon and the gonad developmental process of workers in artificially orphaned colonies are unknown. Although both male and female conspicuous neotenics can emerge as a response to the orphaning of the colony, we observed that majority of the reproductive males that are formed do not molt into the neotenic morph and are therefore inconspicuous in the population. Participation of the inconspicuous reproductive males in sexual reproduction was confirmed by genetic analysis. Slight pigmentation of the abdominal sternites is the only characteristic of the inconspicuous reproductive males that enables them to be distinguished from normal male workers. The presence of the female ergatoid (one type of female neotenic) did not induce the production of inconspicuous reproductive males during the 12-week experiment time.